This invention relates to a solid-material-spreader species of the generic invention which is also embodied in the liquid-spraying species disclosed in the applicant's copending application Ser. No. 685,972, filed May 13, 1976 and entitled "Field-Sprayer Tank-Vehicle Having Means for On-Site Metering and Mixing of Soil-Treating Chemicals."
Field material-distributing machines having vehicle-speed-responsive means for insuring uniform coverage are known (e.g. Hallberg U.S. Pat. No. 3,233,832). But no apparatus is known to have a plurality of relatively small auxiliary tanks for holding and mixing-in on-site, the concentrated chemical additives which heretofore have been pre-mixed with the basic material in the large container of the vehicle. Pre-mixing has the decided disadvantage of making it difficult to prevent waste of materials and/or time. If a field is larger than anticipated, a second trip by the driver will be required. If the field is smaller than expected, waste of valuable chemicals will result. In either case the driver may be tempted to detrimentallyunder-apply or over-apply the dwindling pre-mixed supply. A further disadvantage of conventional pre-mixing is the time-consuming necessity of thoroughly washing-out the large container to remove even traces of chemicals that would be objectionable on a subsequent job.
It is according the principal object of the present invention to provide a field material-spreader vehicle having a plurality of relatively small auxiliary containers for chemical additives for time- and material-saving on-site metered mixing thereof with a hopper-carried base material.
It is another object to provide such a vehicle having speed-variable positive-acting pumps for each line for accurate metering of the several concentrated ingredients, to the conveyor-metered comminuted material.
It is a further object to provide such a device with vehicle-speed-responsive means for insuring uniform application of the controlled-quantities mixture, with or without manually variable application rates to field areas needing more or less added material.
Other objects and advantages will appear as the following detailed description proceeds.